1. Field of the Invention
The present invention relates to fluid injection nozzles that serve to control the flow of a fluid, and in particular to fluid injection nozzles that are adapted to atomize a liquid supplied from a fluid injection valve. The present invention also relates to fluid injectors having such fluid injection nozzles. Such fluid injection nozzles and fluid injectors may be, e.g., utilized within internal combustion engines for vehicles.
2. Description of the Related Art
Japanese Laid-Open Patent Publication No. 11-200998 teaches a fuel injection nozzle as shown in FIG. 7, which shows a cross-sectional view of a part of the fuel injection nozzle, and FIG. 8, which shows a broken-away plan view of the known fuel injection nozzle.
As shown in FIG. 7, a fuel injection valve 101 includes a valve seat 103 and a movable valve 104. The valve seat 103 includes a valve seat surface 103a and an injection hole (port) 103b. The valve seat surface 103a is formed on an inner wall or surface of a fuel flow channel. The injection hole 103b is disposed on the downstream side of the valve seat surface 103a. The valve 104 includes a contact surface 104a that is designed to contact the valve seat surface 103a. 
The fuel injection valve 101 is operable to selectively exhaust fuel via the injection hole 103b when the contact surface 104a of the valve 104 moves away from the valve seat surface 103a of the valve seat 103 (valve opening operation). On the other hand, fuel injection stops when the contact surface 104a of the valve 104 contacts and seals the valve seat surface 103a of the valve seat 103 (valve closing operation).
A fuel injection nozzle 105 is disposed on the bottom or downstream surface of the valve seat 103 and includes upper and lower plate members 151, 153. The upper plate member 151 is disposed so as to contact the bottom surface of the valve seat 103 and includes eight inlet holes 151a (see FIG. 8) that extend through the upper plate member 151.
As shown in FIG. 7, the lower plate member 153 is mounted on the valve seat 103, such that it is disposed on the downstream side (lower side as viewed in FIG. 7) of the upper plate 151. A recess 153b is formed on the upstream side of the lower plate member 153. The recess 153b cooperates with a downstream side surface of the upper plate member 151 and defines a substantially circular fuel chamber 155 between the upper and lower plate members 151, 153. As shown in FIG. 8, the lower plate member 153 includes four outlet holes 153a (see FIG. 8) that extend through the lower plate member 153.
According to the known fuel injection nozzle 105 described above, when the fuel injection valve 101 opens, pressurized fuel is forced through the injection hole 103a of the valve seat 103. The fuel then flows through the inlet holes 151a of the upper plate member 151, through the fuel chamber 155 and then is exhausted through the outlet holes 153a. 
Therefore, according to the known fuel injection nozzle 105, the fuel flows into the fuel chamber 155 from the inlet holes 151a of the upper plate member 151 and then flows horizontally within the fuel chamber 155 along the recess 153b. However, because the inlet holes 151a and the outlet holes 153a are not aligned with each other, the fuel flows into each outlet hole 153a from all directions. Because the outlet holes 153a are inclined relative to the bottom of the recess 153b, the angle of the fuel flow that enters the respective outlet holes 153a varies in response to the direction of the fuel flow within the recess 153b. If an increased amount of fuel flows at an obtuse angle relative to the outlet holes 153, the fuel flow will stabilize, thereby generating atomized fuel particles having relatively large diameters. Because small diameter fuel particles are desired, this known design is disadvantageous.
It is, accordingly, one object of the present invention to teach improved fluid injection nozzles and fluid injection valves that can reliably generate relatively small diameter fuel particles.
According to one aspect of the present teachings, fluid injection nozzles are taught that are arranged and constructed to be mounted on a fluid injector in order to control the flow of a fluid exhausted through an injection hole of the fluid injector. The fluid injection nozzle may include at least one nozzle hole that has an inlet hole, an intermediate hole and an outlet hole. The combination of the inlet hole, the intermediate hole and the outlet hole serves to provide a step-wise control of the flow of the fluid ejected from the injection hole, which preferably serves to atomize the fluid passing through the nozzle hole. The intermediate hole may have a longitudinal axis that extends substantially perpendicularly with respect to a nozzle axis. Further, the intermediate hole may include a first terminal end that communicates with the inlet hole and a second terminal end that communicates the outlet hole. In addition, the intermediate hole may preferably have a substantially uniform width along substantially the entire length of the longitudinal axis. The outlet hole may have a central axis that is displaced from the longitudinal axis of the intermediate hole, such that the central axis and the longitudinal axis do not intersect.
If the fluid flows through the intermediate hole, which intermediate hole has a longitudinal axis that extends substantially perpendicularly with the nozzle axis and has a substantially uniform width along substantially the entire length in the longitudinal axis, direction may be imparted to the fluid flow along the longitudinal direction of the intermediate hole. In other words, the direction of the fluid flow within the intermediate hole may preferably substantially align with the longitudinal axis of the intermediate hole. In addition, if the outlet hole has a central axis that is displaced from the longitudinal axis of the intermediate hole, the center of the fluid flow stream preferably does not turn in the exact opposite direction at the second terminal end of the intermediate hole. As a result backward flow within the intermediate hole can be prevented.
Due to a multiplied or amplified atomization effect imparted to the fluid by causing the fluid to flow along the longitudinal direction of the intermediate hole and preventing backward flow at the second terminal end of the intermediate hole by displacing the central axis of the outlet hole from the longitudinal axis of the intermediate hole, the fluid can be more effectively atomized than in the above-described known injector nozzle.
Preferably, an edge defining an acute angle is formed in the fluid nozzle at a portion of a periphery of the outlet hole that is adjacent to the intermediate hole and is displaced or separated from the second terminal end of the intermediate hole. Therefore, the fluid that has flowed through the intermediate hole enters into the outlet hole and the direction of the flow will abruptly change by an angle of more than 90xc2x0. As a result, the flow of fluid may be effectively bubbled or burbled so as to improve the atomizing effect.
Optionally, the nozzle may include three plate members that are overlaid, or disposed substantially in parallel, with each other. For example, a first plate member may include the inlet hole, a second plate member may include the intermediate hole and a third plate member may include the outlet hole. This design can be utilized to easily and relatively cheaply manufacture a nozzle hole having three holes that are not aligned with each other. However, the three non-aligned holes also may be defined within a single plate or plate member, or within two plate members or plates.
In the present specification, the terms xe2x80x9cnozzle hole,xe2x80x9d xe2x80x9cinlet hole,xe2x80x9d xe2x80x9cintermediate hole,xe2x80x9d and xe2x80x9coutlet holexe2x80x9d may be replaced (or used interchangeably) with xe2x80x9cnozzle passage,xe2x80x9d xe2x80x9cinlet passage,xe2x80x9d xe2x80x9cintermediate passagexe2x80x9d and xe2x80x9coutlet passage.xe2x80x9d Moreover, the terms xe2x80x9caperture,xe2x80x9d xe2x80x9cbore,xe2x80x9d xe2x80x9ccavityxe2x80x9d and xe2x80x9corificexe2x80x9d also may be used interchangeably with xe2x80x9cholexe2x80x9d or xe2x80x9cpassage.xe2x80x9d Furthermore, the terms xe2x80x9cinlet holexe2x80x9d and xe2x80x9coutlet holexe2x80x9d also may be respectively referred to as an xe2x80x9cinlet portxe2x80x9d and an xe2x80x9coutlet port.xe2x80x9d In each case, the intended meaning is the same.
Thus, in another aspect of the present teachings, a fluid nozzle may include at least one nozzle passage that may comprise an inlet passage (port), an intermediate passage and an outlet passage (port). Preferably, the inlet passage is substantially aligned (e.g., substantially parallel) with the direction of fluid flow entering the inlet passage. For example, a fluid injector may supply pressurized fluid to the fluid nozzle and the fluid injector may have a substantially longitudinal axis along which the fluid flows within the fluid injector. Thus, the inlet passage is preferably substantially aligned (or substantially parallel) with the longitudinal axis of the fluid injector. The intermediate passage preferably communicates with the inlet passage and is disposed substantially perpendicular to the inlet passage. The outlet passage preferably communicates with the intermediate passage. Further, a longitudinal (or center) axis of the outlet passage preferably forms an acute angle with a longitudinal (or center) axis of the intermediate passage. Thus, the direction of the fluid flowing through the intermediate passage preferably changes by an angle of more than 90xc2x0 in order to pass from the intermediate passage into the outlet passage. Optionally, the outlet passage may communicate with (or be disposed proximally to) a terminal end of the intermediate passage. In another optional embodiment, the longitudinal (or center) axis of the outlet passage may be displaced from the longitudinal (or center) axis of the intermediate passage, such that these two axes do not intersect.
According to another aspect of the present teachings, fuel injectors are taught that include a fluid nozzle having one or more of the above or below described features.
Additional objects, features and advantages of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims.